LG Refrigerator Error Er dH – Causes & Fix
The automatic defrost didn't finish, so frost is building up on the evaporator coil behind the freezer panel.
At a glance
Severity: Moderate
- Meaning
- Defrost Error – Evaporator Not Defrosting
- Typical repair cost
- $0–$450
- DIY difficulty
- Moderate
Every LG frost-free refrigerator melts the frost off its evaporator coil several times a day by switching on a defrost heater until a defrost sensor on the coil reports that it's warm enough. If the control board runs the heater and the sensor never reaches that temperature within the allowed time, it stores Er dH. Most of the time the heater itself or the thermal fuse in its circuit has opened; a bad sensor or a corroded connector at the coil comes next. Nothing breaks immediately, but frost keeps growing until it chokes the airflow, and then both compartments warm up.
How it looks on the display
Model families & display variants
| Model family | Shows | Note |
|---|---|---|
| Bottom-freezer, French-door and side-by-side models with two readouts | Er dH | Er appears on the freezer readout and dH on the fridge readout, or vice versa. |
| Models with one panel display | dH | The code may blink or alternate with the temperature settings. |
| Models with a separate defrost sensor code | Er dS | dS points directly to the defrost sensor itself; dH means the defrost as a whole didn't complete. |
Safety first · Consult a professional
Unplug the refrigerator before removing the freezer back panel – the defrost heater runs on line voltage and the glass-tube type gets hot enough to burn. Never chip frost off the coil with a sharp tool; a punctured tube leaks refrigerant and can't be fixed as a DIY job.
- Unplug the appliance or switch off the breaker before opening any panel. Mains voltage can kill.
Symptoms
- Er dH on the display (Er on one readout, dH on the other)
- Thick white frost on the back wall of the freezer or visible through the vents
- Freezer and fridge slowly getting warmer over several days
- Fan noise, ticking or scraping as the blade hits ice
- Ice sheet on the freezer floor or water under the crisper drawers
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Defrost heater burned out (open circuit)
- Thermal fuse in the defrost circuit has opened
- Defrost sensor faulty or unplugged
- Corroded or loose connector at the evaporator wiring
- Very heavy frost after a door was left ajar, so defrost ran out of time
- Defrost relay on the main board not switching
Fix it step by step
Read the frost pattern
Look at the coil through the vents or after removing the freezer rear panel. Even, thick frost over the whole coil means the defrost isn't working. Frost only on the first few loops with the rest bare points instead to a refrigerant problem – that's a job for a certified technician.
Tools: Flashlight
Manual defrost to buy time
Empty the freezer into coolers, unplug the fridge and leave the doors open until the coil is completely clear, typically 12–24 hours. Lay towels down for the meltwater. This restores cooling for a few days to a couple of weeks while you track down the failed part.
Tools: Towels & shallow pan
Check the defrost heater
With the fridge unplugged and the rear panel off, disconnect the heater and measure across it with a multimeter. A healthy heater on a 115 V fridge usually reads a few dozen ohms; OL or infinite resistance means it's burned out.
Tools: Multimeter, Screwdriver
Test the thermal fuse
The small fuse clipped to the coil or its tubing should show continuity at room temperature. If it reads open, replace it – and check the heater and sensor too, since a fuse often blows because something else overheated.
Tools: Multimeter
Inspect the sensor and connectors
Look for green corrosion, melted plastic or moisture at the connectors near the coil. Compare the defrost sensor's resistance with the chart on the model's tech sheet; a reading far off or open means replace it.
Tools: Multimeter, Flashlight
Clear the drain before closing up
Pour a cup of warm water into the drain trough under the coil. If it doesn't run away freely, clear the opening; otherwise meltwater will refreeze into a block after the next defrost.
Tools: Towels & shallow pan
How to reset Er dH
- Unplug the refrigerator or switch off its breaker for 5 minutes
- Plug it back in; the code usually clears and returns after the next failed defrost if the fault is still there
- If Er dH comes back within one or two days, the defrost circuit still has an open part
Where the parts are
- 1Evaporator fan
- 2Defrost heater
- 3Temperature sensor
- 4Door switch
- 5Compressor
- 6Condenser
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Manual defrost (temporary fix) | Yes | $0 |
| Defrost heater (part only, DIY install) | Yes | $30–$80 |
| Defrost heater replaced by a technician | No | $200–$380 |
| Thermal fuse or defrost sensor replaced by a technician | No | $150–$300 |
| Main control board replacement | No | $220–$450 |
Rough US estimates; technician call-out fees vary by region. Not a quote.
When to call a technician
Book a technician if you're not comfortable removing the freezer panel and using a multimeter, or if heater, fuse and sensor all test good and Er dH still returns – the board's defrost relay is then likely. Call right away if the frost pattern looks patchy rather than even, because that points to a sealed-system problem that only a certified technician may work on.
Frequently asked questions
Can I keep using the fridge with Er dH?
For a short time. Cooling usually stays normal for days until the frost closes off the airflow. A manual defrost buys time, but the frost will come back until the failed part is replaced.
Why did my fridge work fine for a week after I defrosted it?
A manual defrost clears the ice the automatic system couldn't. The heater, fuse or sensor is still faulty, so frost builds up again at the same rate – that delay is typical of this fault.
Is the defrost heater an easy DIY repair?
On many LG models it's a moderate job: unplug, empty the freezer, remove the rear panel, swap the heater and connectors. Be gentle around the aluminum coil and tubes – a bent or punctured tube ends in a sealed-system repair.
What's the difference between Er dH and Er FF?
Er dH means the defrost didn't finish; Er FF means the freezer fan isn't reporting rotation. They often appear together, because a coil left frozen by a failed defrost can lock the fan.
Sources
- Official LG user documentation and support pages (facts only; wording is our own)
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